Fluid circulation pump



Jan. 30, 1968 I o. RYE 3,366,068

I FLUIDCIRCULATI ON PUMP Filed Sept. 12, 1966 //v VEA/TO/Z, 01/5 fiYE ATTOF/YEKS" United States Patent Ofiice 3,36%,fl68 Patented Jan. 30, l$68 3,366,068 FLUID CKRCULATIQN PUMP I Ove Rye, Aalsgaarde, Denmark, assignor to T. Smedegaard A/S, Glostrup, Denmark, a corporation of Denmark Filed Sept. 12, 1966, Ser. No. 578,660

Claims priority, application Denmark, Sept. 13, 1965,

4,685/65 10 Claims. (Cl. 103-111) The present invention has reference to an improved fluid circulation pump assembly of the type wherein the rotor of an electric motor which drives the impeller of the pump is located in a rotor compartment surrounded by a split tube. This rotor compartment is axially separated from the pressure compartment containing the impeller of the pump, and specificallyby means of an elastic partition wall, the radial inner marginal portion of which is provided with a sealing ring encircling the pump shaft with play, this sealing ring being axially retained by means of spring force against a suitable sealing ring rotating together with the pump shaft.

With such circulation pumps the rotor compartment, upon simultaneous actuation of a venting element at the opposite end of the compartment, is filled with fluid pumped by the impeller of the pump, which fluid or liquid then serves as lubricating agent for the rotor bearings of the electric motor. During filling of the rotor compartment the pressure in the pressure compartment of the pump maintains the sealing ring located at the elastic partition wall, against the action of the spring force, spaced from the sealing ring of the shaft. When the rotor compartment has filled and has received the same pressure as in the pressure compartment of the pump, the elastic partition wall closes the sealing rings against one another. In this manner there is prevented that the liquid in the rotor compartment is continuously replenished which, in the case of a circulation pump for warm consumer water, brings about deposition of lime and impurities in the bearings of the rotor and renders frequent overhauling necessary.

Upon the appearance of temperature or pressure changes during operation of the pump the elastic partition wall compensates for small volume changes of the fluid or liquid in the rotor compartment which are brought about thereby. Should for any reason liquid become lost from the rotor compartment the spring force acting upon the elastic partition wall is overcome, so that both of the sealing rings are separated from one another and permit liquid to flow into the rotor compartment until such is again filled. It can also happen that for some reason the pressure in the rotor compartment, for instance due to an extraordinary temperature increase in the rotor compartment and the pressure compartment of the impeller, cannot be balanced or compensated by the elastic partition wall, and in order to prevent the risk that the partition wall will break it is therefore necessary to provide further measures.

Previously, one was satisfied in retaining the radial external marginal portion of the elastic partition wall against a fixed seat by means of the same spring force which retained the sealing rings against one another. In the presence of too'large a pressure in the rotor compartment the outer marginal portion of the partition wall will thus move away from the seat.

However, this expedient is associated with the drawback that the partition wall can move, which can be disadvantageous from the standpoint of proper impact between the sealing rings and, apart from this, it subjects such to a very considerable overpressure before the spring force which acts upon the sealing rings is overcome. Heretofore, as a safety measure or precaution against overpressure in the rotor compartment there was proposed the utilization of a further pressure spring between the hub or nave of the impeller and the sealing ring rotating together with the pump shaft, which spring can then give and permit the sealing rings to move away from one another upon the presence of an overpressure in the rotor compartment. This previous proposal requires that the movement of the elastic partition wall be limited in a direction towards the impeller by a component or element which is fixed with respect to the pump housing, and such as well as the further spring make the entire arrangement complicated and requiring more space in axial direction.

Now a primary object of the present invention is to provide a teaching of how the elastic partition Wall can be designed to respond as protective arrangement or device in the presence of an overpressure in the rotor compartment without requiring further springs or a greater axial compartment or space.

Another important object of the present invention is to provide an improved fluid circulation pump which effectively responds to overpressure in the rotor compartment of the pump drive motor while overcoming the drawbacks of the prior art structures.

In order to implement these and still further objects of the invention which will become more readily apparent as the description proceeds, the inventive fluid circulation pump is characterized by the features that the radial external marginal or peripheral portion of the elastic partition wall is fixedly retained with respect to the rotor compartment, with the exception of at least one relatively short peripheral section or location which is constructed as check or counter-valve in such a manner that such is effectively opened when there appears a pressure difference in the opposite direction from that which brings about that both sealing rings separate from one another.

The position of the elastic partition wall is thereby insured, so that the sealing rings are always positioned properly in relation to one another, and the short peripheral section or sections of the marginal portion of the partition wall enable quick reactions even with a relatively small overpressure in the rotor compartment.

The elastic partition wall, apart from the features of the invention, can be of optional type, for instance such as the known elastic partition Wall of substantially bellows shape as taught in the British Patent 631,981, and specifically, containing an enclosed helical pressure spring which encircles the pump shaft and which is arranged between the mechanical sealing ring located at the partition wall and the radial outer marginal portion of the bellows constructed as a flange. 'In such case the inventive pump is characterized by the fact that between the spring and the bellows flange there is arranged a preferably cup or dish-shaped spring impact disc or plate, the outer edge of which bearing against the flange is interrupted in front of the or those sections of the flange serving as check or counter valve. Upon the presence of an overpressure in the rotor compartment, the edge of the bellows at the interrupted locations of the edge of the spring disc will bow or arch and fluid can pass through the tunnel-shaped channels which are thereby formed.

The previously mentioned partition wall is manufactured from elastic material which should be able to give, whereas the spring serves to insure for mutual contact of the sealing rings.

A further known form of elastic partition wall comprises a primarily planar, circular, disc or plate-shaped membrane which is connected at its radial inner-marginal portion carrying the sealing ring with the inner edge of a corresponding blade or leaf spring. Such partition walls are, among other things, employed when there exists limited space in axial direction. In the event that such a partition wall is to be used in accordance with the invention, then it can be manufactured in such a manner that the blade spring possesses, at least at one location of its periphery, primarily radially inwardly directed pairs of slits which extend inwardly toward the rotor compartment, and further, that the outer marginal portion of the blade spring, externally of this or these locations, is fixedly retained in known manner. The portion of the blade spring situated between each pair of slits can then easily lift or raise and permit the throughflow of fluid from the rotor compartment without disturbing the remaining position of the partition wall.

The previously discussed embodiment can, according to the invention, be further developed in that, the portion of the blade spring disposed between a pair of associated slits possesses a smaller external diameter than the remainder of the blade spring. The fluid from the rotor compartment, therefore, has associated with it a shorter path during flowing out, and additionally, there is provided the possibility of enclosing the entire path about the edge or margin of the elastic partition wall with an erect or vertical protective ring which can be simultaneously constructed as retaining means or support for the partition wall.

The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawing wherein:

FIGURE 1 is a longitudinal sectional view of a first embodiment of inventive fluid circulation pump, taken through a portion of the pump;

FIGURE 2 is a longitudinal sectional view, similar to the illustration of FIGURE 1, of a further embodiment of inventive pump; and

FIGURE 3 is a fragmentary view showing a detail of the embodiment of pump depicted in FIGURE 2.

Describing now the drawing, in FIGURES 1 and 2 the pump impeller is fixed to a pump shaft 11 revolving in two suitable bearings, of which the lower one is visible and designated by reference character 12. Between these bearings 12 the shaft 11 carries a non-illustrated rotor for an electric motor driving the pump. In the usual manner there is arranged about the rotor a split tube 13 or equivalent structure. The compartment 14 within the split tube 13 will hereinafter convenienly be referred to as the rotor compartment, whereas the compartment or chamber 15 containing the impeller 10 will hereinafter be designated as the pressure compartment. A channel or conduit 16 extends from the rotor compartment or chamber 14 to a chamber or compartment 17 which is separated from the pressure compartment 15 through the intermediary of an elastic partition wall means 18. This partition wall means 18 carries a sealing ring 19 along the peripheral or marginal edge of the opening 18a encircling the pump shaft 11. Sealing ring 19 is normally biased by means of :a suitable spring 20 into contact with a suitable sealing ring 21 rotating together with the pump shaft 11. Now, when the pressure in the rotor compartment 14 falls below a predetermined value the pressure in the compartment 15 moves the sealing ring 19 of the partition wall 18 away from the sealing ring 21 of the pump shaft 11, so that fluid can flow into the rotor compartment 14.

The previously described details are generally known to the art, and both of the embodiments depicted in FIG- URES 1 and 2 differ from one another only insofar as in the case of the embodiment of FIGURE 1 there is used for the spring 20 a helical spring, whereas in the other embodiment of FIGURE 2 such spring is a blade or leaf spring. Now, the helical or spiral spring 20 of FIGURE 1 requires more space in axial direction than the blade spring of FIGURE 2, and this helical spring also requires the use of a spring retainer or support 22 which, as shown to the right of FIGURE 1, has its outer peripheral edge 22a enclosed in the impact flange 23 of the elastic partition wall 18. Since FIGURES 1 and 2 are depicted on the same scale, it will be clearly apparent how much space the helical spring 20 of FIGURE 1 requires. Moreover, in the event it is desired to reduce the axial expanse of the sealing arrangement it will be preferred to employ a blade or leaf spring which is possibly cup or dishshaped towards the top and approximately of the form of the depicted retainer 22, and to permit the partition wall to remain planar or to follow the curvature of the blade spring toward the top.

One of the most important aspects of the present invention will be ascertained by referring to the left side of FIGURES 1 and 2. In the first embodiment of FIGURE 1 the marginal or peripheral portion 22a of the spring retainer 22 situated at the partition wall flange 23 is merely cut-away or removed at a short location in the peripheral direction. When an overpressure exists in the rotor compartment 14 and, therefore, also in the compartment 17, then the flange 23 at this location or path is pushed away from contact with the stationary portion of the pump housing H, so that the overpressure is balanced or compensated by the thereby formed tunnelshaped throughpassage.

In the event the partition wall is of increased strength or thickness, then it can be necessary to provide it with holes or apertures which extend from the compartment 17 to the impact side of the flange.

In FIGURE 1 the spring 20 does not have any influence upon pushing away of the partition wall flange 23. In contrast thereto, such is the case with the embodiment of FIGURE 2 in that the blade or leaf spring 20 is fixedly clamped along its outer edge or margin against the partition wall 18 which, in this case, does not have to be elastic in the normal sense, such as rubber, rather it can be very thin providing that it is fluid tight. A suitable material for this purpose is Teflon or another suitable mold or formable material. At this or these locations which are provided for passing fluid during overpressure in the rotor compartment, the blade spring 20 is provided with two slots or cuts 24 which extend inwardly from its periphery and which can be directed parallel or radially to the center of the blade spring. Moreover, these cut-outs or slots 24 extend inwardly to such an extent that they terminate inside at the compartment 17. When an overpressure exists in this compartment 17 the leg or flap means 25 of the blade spring 20 situated between the slots 24 will be able to bias away, and specifically, independently of the edges bordering at the blade spring. This spring action can be rendered easier in that the leg or flap 25 is provided with a hole 26 or other apertures, so that there only remain narrow strips 2517 as the connection to the inwardly disposed portion of the blade spring 20.

The partition wall 18 covers these holes or apertures so that only fluid or liquid can pass the flaps or legs 25 along its peripheral edge 25a. As shown, this edge 25a can, if desired, be displaced or retracted somewhat inwardly with respect to the remaining edges of the blade spring 20, so that liquid begins to flow past immediately and the leg will only be moved or raised slightly. In this manner the entire arrangement becomes exceptionally sensitive and responds to a very small overpressure.

It should be clear that the blade spring 20 at the location of the leg or flap 25, or in the case of a number of such legs, is not held tensioned against the partition wall 18, in that the leg will then not be able to raise or move away. In FIGURE 2 there is depicted an advantageous and simple manner .of fixedly clamping the blade spring 20 by means of a beaded or flanged-over annular edge 27 of a retainer or support 28 and which presses against the blade spring 20. At the location of the flap or leg 25 the flanged edge, as best shown at the left of FIGURE 2, is removed or cut-away, so that the partition wall 18 and the flap or leg can, at this location, freely bend axially without being radially displaced.

While there is shown and described present preferred embodiments of the invention it is to be distinctly understood that the invention is not limited thereto 'but may be otherwise variously embodied and practiced within the scope of the following claims.

What is claimed is:

ll. A fluid circulation pump assembly of the type wherein the rotor of an electric motor driving the pump impeller is located in a rotor compartment enclosed by a tube means comprising, in combination, a pressure compartment, a pump impeller and a pump shaft for said pump impeller located in said pressure compartment, elastic partition wall means for separating said pressure compartment from the rotor compartment, said elastic partition wall means having a radial inner marginal portion, a sealing ring carried for rotation by said pump shaft, a spring-loaded sealing ring biased axially against said rotatable sealing ring and adapted to encircle the pump shaft with play carried by said radial inner marginal portion of saidelastic partition wall means, said elastic partition wall means having a radial outer marginal portion, a short peripheral section of said radial outer marginal portion of said elastic partition Wall means being constructed as counter valve means, said outer marginal portion of said elastic partition wall means with the exception of the short peripheral section being retained stationary with respect to said rotor compartment, said counter valve means operating in a manner that the latter is opened upon the presence of a pressure difference which works in opposite direction from that direction which causes both of said sealing rings to separate from one another.

2, A fluid circulation pump assembly as defined in claim 1, wherein said elastic partition wall means is substantially bellows-shaped, said outer marginal portion of said bellows-shaped elastic partition wall means being constructed as flange means, said bellows-shaped elastic partition wall means containing a helical pressure spring encircling said pump shaft, said helical pressure spring being located between said sealing ring arranged at said elastic partition wall means and said flange means of said bellows-shaped elastic partition wall means, a spring-impact plate disposed between said helical pressure spring and said flange means, said spring-impact plate having an outer edge portion arranged at said flange means, said outer edge portion of said spring-impact plate being interrupted in front of said short peripheral section of said flange means of said elastic partition wall means constructed as counter valve means.

3. A fluid circulation pump assembly as defined in claim 2, wherein said spring-impact plate is preferably substantially dish-shaped.

4. A fluid circulation pump assembly as defined in claim 1 wherein said elastic partition wall means is constructed to possess the form of a primarily substantially planar, circular disc-shaped membrane, a corresponding blade spring means having a radial inner edge portion at which there is connected said radial inner marginal portion of said elastic partition wall means carrying said sealing ring, said blade spring means being provided at least at one location of its periphery with substantially radially inwardly directed pairs of slot means Which extend inwardly toward said rotor compartment, the outer marginal portion of said blade spring means externally of said location being fixedly retained.

5. A fluid circulation pump assembly as defined in claim 4 wherein the portion of said blade spring means disposed between an associated pair of slot means possesses a smaller external diameter than the remainder of said blade spring means.

=6. A fluid circulation pump assembly comprising,

means providing a rotor compartment and a pressure compartment,

a pump impeller and a pump shaft disposed in said pressure compartment,

a sealing ring carried for rotation by said pump shaft,

an elastic partition wall means carrying a sealing ring,

said elastic partition wall means separating said r0- tor compartment and said pressure compartment from one another, said elastic partition wall means being resiliently biased such that its sealing ring is brought into contact with said sealing ring of said pump shaft,

said elastic partition wall means at least at one portion of the periphery thereof being constructed to provide valve means which open upon the presence of a pressure difference which acts in a direction opposite from that which causes both of said sealing rings to move apart.

7. A fluid circulation pump assembly as defined in claim 6, wherein said elastic partition wall means comprises a partition member, spring means for biasing said sealing ring of said elastic partition wall means against said rotatable sealing ring.

8. A fluid circulation pump assembly as defined in claim 7, wherein said partition member has an outer marginal portion providing flange means, a spring-impact plate against which bears said spring means, said springimpact plate being carried by said flange means of said partition member with the exception of at least one section thereof which is interrupted at said one portion of said periphery of said elastic partition Wall means providing said valve means.

9. A fluid circulation pump assembly as defined in claim 7, wherein said partition member comprises a substantially circular disc-shaped membrane, said spring means being a blade spring connected with said discshaped membrane, said blade spring having at least one pair of associated slits directed inwardly from the periphery thereof to define therebetween at least one flap member at said one portion of said periphery of said elastic partition wall means providing said valve means.

10. A fluid circulation pump assembly as defined in claim 9, wherein said flap member has an outermost peripheral edge which is inset with respect to the external diameter of the remainder of said blade spring.

References Cited UNITED STATES PATENTS 2,650,117 8/1953 Chambers et al. 27742 2,881,015 4/1959 Wahl 277-9O 3,007,724 11/1961 Amirault et al, 277-42 3,137,237 6/1964 Zagar et al. lO3-l11 FOREIGN PATENTS 81 1,849 4/ 1959 Great Britain.

HENRY F. RADUAZO, Primary Examiner. 

1. A FLUID CIRCULATION PUMP ASSEMBLY OF THE TYPE WHEREIN THE ROTOR OF THE ELASTIC MOTOR DRIVING THE PUMP IMPELLER IS LOCATED IN A ROTOR COMPARTMENT ENCLOSED BY A TUBE MEANS COMPRISING, IN COMBINATION, A PRESSURE COMPARTMENT, A PUMP IMPELLER AND A PUMP SHAFT FOR SAID PUMP IMPELLER LOCATED IN SAID PRESSURE COMPARTMENT, ELASTIC PARTITION WALL MEANS FOR SEPARATING SAID PRESSURE COMPARTMENT FROM THE ROTOR COMPARTMENT, SAID ELASTIC PARTITION WALL MEANS HAVING A RADIAL INNER MARGINAL PORTION, A SEALING RING CARRIED FOR ROTATION BY SAID PUMP SHAFT, A SPRING-LOADED SEALING RING BIASED AXIALLY AGAINST SAID ROTATABLE SEALING RING AND ADAPTED TO ENCIRCLE THE PUMP SHAFT WITH PLAY CARRIED BY SAID RADIAL INNER MARGINAL PORTION OF SAID ELASTIC PARTITION WALL MEANS, SAID ELASTIC PARTITION WALL MEANS HAVING A RADIAL OUTER MARGINAL PORTION, A SHORT PERIPHERAL SECTION OF SAID RADIAL OUTER MARGINAL PORTION OF SAID ELASTIC PARTITION WALL MEANS BEING CONSTRUCTED AS COUNTER VALVE MEANS, SAID OUTER MARGINAL PORTION OF SAID ELASTIC PARTITION WALL MEANS WITH THE EXCEPTION OF THE SHORT PERIPHERAL SECTION BEING RETAINED STATIONARY WITH RESPECT TO SAID ROTOR COMPARTMENT, SAID COUNTER VALVE MEANS OPERATING IN A MANNER THAT THE LATTER IS OPENED UPON THE PRESENCE OF A PRESSURE DIFFERENCE WHICH WORKS IN OPPOSITE DIRECTION FROM THAT DIRECTION WHICH CAUSES BOTH OF SAID SEALING RINGS TO SEPARATE FROM ONE ANOTHER. 